The AJM process involves removing material from a workpiece using abrasive particles carried by a high-velocity gas stream. The abrasive particles impact the workpiece surface at high velocities, causing brittle fractures and removing small fragments of material. AJM can machine hard and brittle materials and reach difficult internal areas due to the flexible hose used to direct the abrasive stream. It generates less heat than conventional machining and does not require direct tool-workpiece contact. Common applications include cutting glass and ceramics, deburring metal parts, and cleaning or dressing grinding wheels.

1. In
v
pr
im
su
al
ab
m
ce
ed
th
F
A
Module
n abrasive je
elocity air
ropelled by
mpact of th
urface of the
lso called as
brasive micr
machining m
eramics. Typ
dges. The pr
he tool neve
igure 3.3.1
Advantages
e-3: ADV
Abras
et machining
/ gas stream
a high veloc
e abrasive p
e workpiece
s abrasive bl
ro-blasting, p
method for h
pically the p
rocess is inh
er touches th
ANCED M
Lec
ive Jet Mac
g (AJM) ma
m of abrasi
city gas to er
particles on
and the carr
lasting proce
pencil blasti
hard and bri
process is u
herently free
he substrate.
MATERIA
cture No-3
chining (AJM
aterial remov
ive particles
rode materia
n the workp
rier gas carri
ess. It is also
ing and micr
ittle materia
sed for cutti
e from chatt
The schem
AL REMO
M)
val occurs o
s on the wo
al from the w
piece, tiny b
ies away the
o known by
ro-abrasive b
als such as
ing intricate
ter, vibration
matic of AJM
OVAL PR
on account o
orkpiece. Th
workpiece. A
brittle fractu
e fractured fr
several oth
blasting. AJ
glass, silico
e shapes or f
n and heat p
M process se
ROCESSES
of impact of
he abrasive
As an outcom
ures occur a
ragments. AJ
er names su
JM is an effe
on, tungsten
forms of spe
problems bec
et up is show
S
f high
s are
me of
at the
JM is
uch as
ective
n and
ecific
cause
wn in

2.  AJM process is a highly flexible process wherein the abrasive media is carried by
a flexible hose, which can reach out to some difficult areas and internal regions.
 AJM process creates localized forces and generates lesser heat than the
conventional machining processes.
 There is no damage to the workpiece surface and also the process does not have
tool-workpiece contact, hence lesser amount of heat is generated.
 The power consumption in AJM process is low.
Disadvantages
 The material removal rate is low
 The process is limited to brittle and hard materials
 The wear rate of nozzle is very high
 The process results in poor machining accuracy
 The process can cause environmental pollution
Applications:
Metal working:
 De-burring of some critical zones in the machined parts.
 Drilling and cutting of the thin and hardened metal sections.
 Removing the machining marks, flaws, chrome and anodizing marks.
Glass:
 Cutting of the optical fibers without altering its wavelength.
 Cutting, drilling and frosting precision optical lenses.
 Cutting extremely thin sections of glass and intricate curved patterns.
 Cutting and etching normally inaccessible areas and internal surfaces.
 Cleaning and dressing the grinding wheels used for glass.
Grinding:
 Cleaning the residues from diamond wheels, dressing wheels of any shape and
size.
Principle of AJM

3. The principle of machining / cutting by abrasive jet process is explained through the
following steps:
1. Abrasive particles of size between 10 m to 50 m (depending upon the
requirement of either cutting or finishing of the workpiece) are accelerated in a
gas stream (commonly used gas stream is air at high atmospheric pressures).
2. The smaller abrasive particles are useful for finishing and bigger are used for
cutting operations.
3. The abrasive particles are directed through the nozzle, towards the workpiece
surface where-ever cutting or finishing is to be done. The distance between the tip
of the nozzle and the work surface is normally within 1 mm.
4. As the abrasive particles impact the surface of the workpiece, it causes a small
fracture at the surface of the workpiece. The material erosion occurs by the
chipping action.
5. The erosion of material by chipping action is convenient in those materials that
are hard and brittle.
6. As the particles impact the surface of workpiece, it causes a small fracture and
wear, which is carried away by the gas along with the abrasive particles.
7. The abrasive particles once used, cannot be re-used as its shape changes partially
and the workpiece material is also clogged with the abrasive particles during
impingement and subsequent flushing by the carrier gas.